Approach to risk stratification for papillary thyroid carcinoma based on molecular profiling: institutional analysis.

BACKGROUND: Currently, treatment recommendations for papillary thyroid carcinoma are not based on the genetic background causing tumourigenesis. The aim of the present study was to correlate the mutational profile of papillary thyroid carcinoma with clinical parameters of tumour aggressiveness, to establish recommendations for risk-stratified surgical treatment. METHOD: Papillary thyroid carcinoma tumour tissue of patients undergoing thyroid surgery at the University Medical Centre Mainz underwent analysis of BRAF, TERT promoter and RAS mutational status as well as potential RET and NTRK rearrangements. Mutation status was correlated with clinical course of disease. RESULTS: One hundred and seventy-one patients operated for papillary thyroid carcinoma were included. The median age was 48 years (range 8-85) and 69 per cent (118/171) of patients were females. One hundred and nine papillary thyroid carcinomas were BRAF-V600E mutant, 16 TERT promotor mutant and 12 RAS mutant; 12 papillary thyroid carcinomas harboured RET rearrangements and two papillary thyroid carcinomas showed NTRK rearrangements. TERT promoter mutant papillary thyroid carcinomas had a higher risk of distant metastasis (OR 51.3, 7.0 to 1048.2, P < 0.001) and radioiodine-refractory disease (OR 37.8, 9.9 to 169.5, P < 0.001). Concomitant BRAF and TERT promoter mutations increased the risk of radioiodine-refractory disease in papillary thyroid carcinoma (OR 21.7, 5.6 to 88.9, P < 0.001). RET rearrangements were associated with a higher count of tumour-affected lymph nodes (OR 7950.9, 233.7 to 270495.7, P < 0.001) but did not influence distant metastasis or radioiodine-refractory disease. CONCLUSIONS: Papillary thyroid carcinoma with concomitant BRAF-V600E and TERT promoter mutations demonstrated an aggressive course of disease, suggesting the need for a more extensive surgical strategy. RET rearrangement-positive papillary thyroid carcinoma did not affect the clinical outcome, potentially obviating the need for prophylactic lymphadenectomy.

Detection of Cellular Senescence Reveals the Existence of Senescent Tumor Cells within Invasive Breast Carcinomas and Related Metastases.

Oncogene-induced senescence is thought to constitute a barrier to carcinogenesis by arresting cells at risk of malignant transformation. However, numerous findings suggest that senescent cells may conversely promote tumor growth and metastatic progression, for example, through the senescence-associated secretory phenotype (SASP) they produce. Here, we investigated the degree to which senescent tumor cells exist within untreated human primary breast carcinomas and whether the presence of senescent cancer cells in primary tumors is recapitulated in their matched lymph node metastases. For the detection of senescence, we used SA-ß-galactosidase (SA-ß-gal) staining and other senescence markers such as Ki67, p21, p53, and p16. In patients with invasive luminal A and B breast carcinomas, we found broad similarities in the appearance of cancer cells between primary tumors and their corresponding metastases. Analysis of lymph nodes from patients with other breast cancer subtypes also revealed senescent tumor cells within metastatic lesions. Collectively, our findings show that senescent tumor cells exist within primary breast carcinomas and metastatic lesions. These results suggest a potential role for senescent breast tumor cells during metastatic progression and raise the question as to whether the targeting of senescent tumor cells with anti-senescent drugs might represent a novel avenue for improved treatment of breast and other cancers.

Multiomic analysis of papillary thyroid cancers identifies BAIAP2L1-BRAF fusion and requirement of TRIM25, PDE5A and PKCδ for tumorigenesis.

BACKGROUND: Papillary thyroid carcinoma (PTC) is one of the most common forms of thyroid cancer with a cure rate of over 90% after surgery. However, aggressive forms may still occur, and personalized therapeutic strategies are increasingly required. METHODS: We performed integrated genomic and proteomic analysis of PTC tumor samples from patients who did not harbor BRAF or RAS mutations. We validate the analysis and present in-depth molecular analysis of the identified genetic rearrangement by employing biochemical and cell biological assays. Finally, we employ 3D spheroid models, loss of function studies and chemical inhibitors to target the hitherto upregulated factors. The data are analysed with appropriate statistical tests which are mentioned in the legends section. RESULTS: In a 23-year-old patient with thyroiditis, we identified a novel rearrangement leading to a BAIAP2L1-BRAF fusion that transforms immortalized human thyroid cells in a kinase and CC-domain dependent manner. Moreover, quantitative proteomic analysis of the same patient samples revealed the upregulation of several proteins including the Ubiquitin E3 ligase TRIM25, PDE5A, and PKCδ. Further, in a cohort of PTC patients, we observed higher expression of TRIM25 and PKCδ in the tumor and metastatic lesions, when compared to the matched normal tissue. Inhibition of TRIM25, PDE5A and PKCδ with small molecules or RNA interference affected not only viability and proliferation of BAIAP2L1-BRAF transformed cells, but also the viability, growth and invasion of corresponding 3D spheroid cultures. CONCLUSIONS: Apart from unveiling a novel oncogenic BRAF fusion in PTCs, our data may open a novel avenue of therapeutic targeting in human PTCs.

Second MAFA Variant Causing a Phosphorylation Defect in the Transactivation Domain and Familial Insulinomatosis.

Adult-onset familial insulinomatosis is a rare disorder with recurrent, severe hypoglycemia caused by multiple insulin-secreting pancreatic tumors. The etiology was unclear until the variant p.Ser64Phe in the transcription factor MAFA, a key coordinator of ß-cell insulin secretion, was defined as the cause in two families. We here describe detailed genetic, clinical, and family analyses of two sisters with insulinomatosis, aiming to identify further disease causes. Using exome sequencing, we detected a novel, heterozygous missense variant, p.Thr57Arg, in MAFA's highly conserved transactivation domain. The impact of the affected region is so crucial that in vitro expression studies replacing Thr57 have already been performed, demonstrating a phosphorylation defect with the impairment of transactivation activity and degradation. However, prior to our study, the link to human disease was missing. Furthermore, mild hyperglycemia was observed in six additional, heterozygote family members, indicating that not only insulinomatosis but also MODY-like symptoms co-segregate with p.Thr57Arg. The pre-described MAFA variant, p.Ser64Phe, is located in the same domain, impairs the same phosphorylation cascade, and results in the same symptoms. We confirm MAFA phosphorylation defects are important causes of a characteristic syndrome, thus complementing the pathophysiological and diagnostic disease concept. Additionally, we verify the high penetrance and autosomal dominant inheritance pattern.

Improved detection of sentinel lymph node metastases allows reliable intraoperative identification of patients with extended axillary lymph node involvement in early breast cancer.

BACKGROUND: An improved procedure that allows accurate detection of negative sentinel lymph node (SLN) and of SLN macrometastases during surgery would be highly desirable in order to protect patients from further surgery and to avoid unnecessary costs. We evaluated the accuracy of an intraoperative procedure that combines touch imprint cytology (TIC) and subsequent frozen section (FS) analysis. 2276 SLNs from 1072 patients with clinical node-negative early breast cancer were evaluated during surgery using TIC. Only cytologically-positive SLN were subsequently analysed with a single FS, preserving cytologically-negative SLN for the final postoperative histological diagnosis. Sensitivity, specificity and the accuracy of this approach were analysed by comparing the results from intra- and postoperative SLN and axillary node evaluation. This intraoperative method displayed 100% specificity for SLN metastases and was significantly more sensitive for prognostically relevant macrometastases (85%) than for micrometastases (10%). Sensitivity was highest for patients with two or more positive LNs (96%) than for those with only one (72%). 98% of the patients with final pN2a-pN3a were already identified during surgery. Patients who received primary axillary lymph node dissection had significantly more frequent metastases in further LNs (44.6%). Sensitivity was highest for patients with luminal-B, HER2+ and triple negative breast cancer and for any subtype if Ki-67 > 40%. TIC and subsequent FS of cytologically-positive SLNs is highly reliable for detection of SLN macrometastases, and allows accurate identification of patients with a high risk of extended axillary involvement during surgery, as well as accurate histological diagnosis of negative SLN.

Proteogenomics analysis unveils a TFG-RET gene fusion and druggable targets in papillary thyroid carcinomas.

Papillary thyroid cancer (PTC) is the most common type of endocrine malignancy. By RNA-seq analysis, we identify a RET rearrangement in the tumour material of a patient who does not harbour any known RAS or BRAF mutations. This new gene fusion involves exons 1-4 from the 5' end of the Trk fused Gene (TFG) fused to the 3' end of RET tyrosine kinase leading to a TFG-RET fusion which transforms immortalized human thyroid cells in a kinase-dependent manner. TFG-RET oligomerises in a PB1 domain-dependent manner and oligomerisation of TFG-RET is required for oncogenic transformation. Quantitative proteomic analysis reveals the upregulation of E3 Ubiquitin ligase HUWE1 and DUBs like USP9X and UBP7 in both tumor and metastatic lesions, which is further confirmed in additional patients. Expression of TFG-RET leads to the upregulation of HUWE1 and inhibition of HUWE1 significantly reduces RET-mediated oncogenesis.

ANKRD26-RET - A novel gene fusion involving RET in papillary thyroid carcinoma.

BACKGROUND: Rearrangements of RET are drivers of oncogenesis, traceable in different cancer types as papillary thyroid carcinoma (PTC), non-small cell lung cancer, colorectal or breast cancer. Anchored multiplex PCR based next-generation sequencing (NGS) can detect RET rearrangements involving previously unknown partner genes. METHODS: A sample of PTC underwent NGS, following detection of RET rearrangement by fluorescence in situ hybridization. Expression analysis of ANKRD26 and RET was performed for the tumor harboring ANKRD26-RET, for corresponding normal thyroid tissue and PTC tumors with representative genetic alterations (BRAFV600E, CCDC6-RET), complemented by a comparative search in the "UniProt" database. RESULTS: NGS analysis resulted in the discovery of the fusion ANKRD26-RET. ANKRD26 mRNA was expressed in all PTC tumors (ANKRD26-RET, BRAFV600E, CCDC6-RET) and in normal thyroid tissue, whereas RET mRNA was detected only in the tumors with RET rearrangement. On protein level, ANKRD26-RET combines the RET tyrosine kinase to ankyrin repeat and coiled-coil domains. CONCLUSIONS: ANKRD26-RET is a novel rearrangement of the RET gene, associated with RET expression in thyroid tissue. The result is a fusion of the RET tyrosine kinase to prominent protein-protein interaction motifs. Further studies are required to investigate the influence of different RET rearrangements on metastasis and disease-free survival in PTC.

PD-L1 Expression and Immune Cell Infiltration in Gastroenteropancreatic (GEP) and Non-GEP Neuroendocrine Neoplasms With High Proliferative Activity.

The potential of neuroendocrine neoplasms (NEN) to respond to checkpoint inhibitors is largely unknown and full of great expectations. Immunohistochemical (IHC) studies of programmed cell death ligand 1 (PD-L1) expression in the tumor microenvironment and its implications in predicting the response to checkpoint inhibition is a very active subject. Currently, the combined analysis of PD-L1 expression and tumor-associated immune cell (TAIC) infiltration is considered the best predictive marker of therapeutic response. Here we investigated the expression of PD-L1 on tumor cells (TC) and tumor-infiltrating immune cells (IC) by IHC in 68 NEN samples with a high proliferation rate (Ki-67 >20%) from 57 patients and in 22 samples we correlated it with TAIC density by assessing intratumoral infiltration of CD3+, CD8+, and CD68+ cells. Furthermore, the tumor microenvironment was evaluated according to the classification of Teng et al. We detected PD-L1 expression in 31.6% of NEN G3. Its expression usually was weak and more IC than TC expressed PD-L1. The proportion of tumors positive for PD-L1 was comparable in NEN from different sites of origin but varied depending on tumor differentiation and disease extension. No positive IHC staining was found in 3 well-differentiated neuroendocrine tumors (NETs) with a proliferation rate above 20% (NET G3). When analyzing TAIC, we rarely (18.2%) detected intratumoral CD8+ cells, whereas infiltration by CD3+ and CD68+ cells was more common (45.5 and 59.1%, respectively). By combining CD3+ cells and PD-L1 status, we identified the immune ignorant phenotype of tumor microenvironment as being the most common phenotype, supporting the concept of a preferably combined immunotherapeutic approach in neuroendocrine carcinoma (NEC).

Expression and prognostic significance of insulin­like growth factor-2 receptor in human hepatocellular carcinoma and the influence of transarterial chemoembolization.

Hepatocellular carcinoma (HCC) is one of the most common human malignancies, the incidence of which is growing worldwide. The prognosis of HCC is very poor and it is often accompanied by a high rate of recurrence. Conventional chemotherapeutic approaches are largely inefficient. In order to develop novel effective methods for the early detection and prognosis of HCC, novel markers and therapeutic targets are urgently required. The present study focused on the effects of the expression of the tumor suppressor gene insulin­like growth factor­2 receptor (IGF2R) on patient survival and tumor recurrence in patients with HCC; this study paid specific attention to the influence of transarterial chemoembolization (TACE) prior to surgery. The mRNA expression levels of IGF2R were measured in primary human HCC and corresponding non­neoplastic tumor­surrounding tissue (TST) by reverse transcription­polymerase chain reaction (RT­PCR) (n=92). Subsequently, the associations between IGF2R expression and clinicopathological parameters, outcomes of HCC and TACE pretreatment prior to surgery were determined. Furthermore, the effects of the IGF2R gene polymorphisms rs629849 and rs642588 on susceptibility and on clinicopathological features of HCC were investigated. RT­PCR demonstrated that the mRNA expression levels of IGF2R were downregulated in HCC compared with in TST samples (P=0.004), which was associated with a worse recurrence­free survival of patients with HCC (P=0.002) and a lower occurrence of cirrhosis (P=0.05). TACE­pretreated patients with HCC (n=26) exhibited significantly higher IGF2R mRNA expression in tumor tissues (P=0.019). In addition, significantly more patients with HCC in the TACE­pretreated group exhibited upregulated IGF2R mRNA expression compared with in the non­treated patients (P=0.032). The IGF2R SNPs rs629849 and rs642588 were not significantly associated with HCC risk, whereas a homozygous IGF2R rs629849 GG genotype was associated with a significantly elevated risk of non­viral liver cirrhosis (P=0.05). In conclusion, these data suggested an important role for IGF2R expression in HCC, particularly with regards to TACE treatment prior to surgery.

Safety and efficacy of afatinib as add-on to standard therapy of gemcitabine/cisplatin in chemotherapy-naive patients with advanced biliary tract cancer: an open-label, phase I trial with an extensive biomarker program.

BACKGROUND: To date, the cornerstone of treatment in patients with advanced or metastatic cholangiocarcinoma (CCA) is systemic chemotherapy based on a combination of gemcitabine and a platinum derivative. Other therapeutic approaches including targeted agents and tyrosine kinase inhibitors (TKI) have demonstrated disappointing results, highlighting the complexity of CCA. Recently, drugs aiming at the inhibition of HER-receptors have shown first therapeutic benefit in patients with late stage disease. The aim of this phase I study was to test the dose level toxicities (DLTs), safety and efficacy of afatinib, a highly specific panErbB family receptor TKI, in chemotherapy naive patients with advanced CCA in conjunction with an extensive biomarker program. METHODS: Afatinib was administered continuously p. o. as add-on in patients with advanced CCA who received conventional chemotherapy with gemcitabine/cisplatin. A classical 3 + 3 phase I study was employed, while the maximum tolerated dose (MTD) of oral afatinib was determined in a 2 step dose escalation. Safety, overall survival (OS) and progression free survival (PFS) were evaluated for all patients. Finally, a translational biomarker analysis was conducted for the EGFR and VEGF signalling cascades. RESULTS: Overall, 9 patients were enrolled. Further recruitment was discontinued due to lack of efficacy results of the tested drug in other indications. 30 mg afatinib could be safely administered as add-on to 80% of standard dose gemcitabine/cisplatin. The mOS and mPFS were 7.7 and 6.0 months, respectively. Diarrhoea and haematological disorders were the most common observed AEs. Almost all patients overexpressed EGFR on their tumour tissues, whereas none of them expressed mutations in Exons 18, 19 and 21. Non-responders showed a higher variation of VEGF-C, -D, leptin and sEGFR in their sera. CONCLUSIONS: Afatinib failed to show survival benefits in combination with gemcitabine/cisplatin in patients with advanced CCA. Mutational analysis of EGFR and pathways associated with VEGF-C, -D and leptin might show promising results in future studies. CLINICAL TRIALS REGISTRATION: NCT01679405 August, 2012.

Detection of RET rearrangements in papillary thyroid carcinoma using RT-PCR and FISH techniques - A molecular and clinical analysis.

INTRODUCTION: Oncogenic BRAF and RAS mutations as well as multiple known (and yet unknown) RET fusion oncogenes comprise the majority of causative molecular alterations in papillary thyroid carcinoma (PTC). Apparently "mutation-negative" PTCs encompass a heterogenous group impeding analysis of prognostic significance of underlying genetics. MATERIAL AND METHODS: BRAF wild type PTC tissue of 56 patients was analyzed using two established methods: hybrid-specific RT-PCR for the predominant rearrangement RET/PTC1 and fluorescent in situ hybridization (FISH). Clinical features of the cases with and without RET rearrangement were compared (patient age, gender, tumor size, focality, lymph node affection, and iodine avidity). RESULTS: RT-PCR revealed RET/PTC1 rearrangements in five of 56 tumors (9%). FISH confirmed these, and identified four additional RET rearrangements (9/56; 16%). Loss of the iodine avidity only occurred in cases of RET/PTC hybrids (7/9 tumors), but not in RET/PTC-negative PTCs (0/41 tumors with available uptake information; p = 0.029). The risk to develop lymph node metastases was eight times higher in presence of RET rearrangements (p = 0.010). CONCLUSIONS: FISH analysis, in contrast to hybrid-specific RT-PCR, revealed infrequent and unknown RET fusion genes. The presence of RET rearrangements was associated with a significantly elevated risk to develop iodine refractory disease and lymph node metastases. Of note, significant clinical discrimination was only achievable when taking the FISH results into account; differences would have been missed when using the RT-PCR method only. Increasing evidence of the clinical impact of RET/PTC-positivity may influence the decision on the extent of surgical resection, especially on lymph node dissection, in PTCs.

Novel rearrangements involving the RET gene in papillary thyroid carcinoma.

BACKGROUND: In the field of gene fusions driving tumorigenesis in papillary thyroid carcinoma (PTC), rearrangement of the proto-oncogene RET is the most frequent alteration. Apart from the most common rearrangement of RET to CCDC6, more than 15 partner genes are yet reported. The landscape of RET rearrangements in PTC ("RET-PTC") can notably be enlarged by modern targeted next-generation sequencing, indicating similarities between oncogenic pathways in other cancer types with identical genetic alterations. METHODS: Targeted next-generation sequencing was performed for two cases of BRAF-wild type PTC with confirmation of the results by Sanger sequencing. A "UniProt" database research was performed to assess protein alterations resulting from RET rearrangements. RESULTS: RUFY2-RET and KIAA1468-RET were detected. The fusion genes were not present in normal tissue of the index patients. The rearrangement RUFY2-RET lead to a fusion of the RET tyrosine kinase domain to a RUN domain and a coiled-coil domain. For KIAA1468-RET, a fusion to a LisH domain and two coiled-coil domains resulted. CONCLUSIONS: RUFY2-RET and KIAA1468-RET are novel RET/PTC rearrangements. The fusions were previously described in non-small cell lung cancer. The rearrangement results in a fusion of the RET tyrosine kinase to regulatory domains of RUFY2 and KIAA1468.

Lapatinib with ECF/X in the first-line treatment of metastatic gastric cancer according to HER2neu and EGFR status: a randomized placebo-controlled phase II study (EORTC 40071).

PURPOSE: HER2-targeted therapy with trastuzumab and (CF/X) prolonged overall survival (OS) in metastatic HER2neu+ gastric carcinoma (GC). Lapatinib inhibits both EGFR and HER2neu. We investigated the efficacy and safety of lapatinib with epirubicin (E) + CF/X in GC according to HER2neu and EGFR status. METHODS: Tumors from chemotherapy-naïve patients were screened centrally by fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC). Patients with EGFR and/or HER2neu expression or amplification were allocated to three strata based on EGFR/HER2neu status and were randomized to lapatinib (arm A) or placebo (arm B), with 6 cycles of ECF or ECX (investigator-selected). The primary endpoint was progression-free survival (PFS) in stratum 3. RESULTS: 29 of 72 screened patients were randomized to strata 1 (HER2neu+: by FISH and IHC, n = 6), 2 (HER2neu-: by FISH/+ by IHC, n = 5) and 3 (HER2neu-/EGFR+, n = 18), of which 28 patients were eligible (14 per arm). Enrollment was curtailed after announcement of the negative LOGiC trial results. Median PFS was 8.0 versus 5.9 months (HR = 0.86, 95% CI 0.37-1.99) in the per protocol population, and 8.0 versus 6.3 months (HR = 0.85, 95% CI 0.30-2.46) for stratum 3, in the lapatinib versus placebo arm respectively. Median OS was 13.8 versus 10.1 months, respectively (HR = 0.90, 95% CI 0.35-2.27). There were no safety concerns. CONCLUSIONS: Central EGFR and HER2neu stratification by IHC and FISH can be used for further pan-HER strategies. Lapatinib with ECF/X was well tolerated, but did not show clear activity in patients with metastatic GC.

Progression of transthyretin (TTR) amyloidosis in donors and recipients after domino liver transplantation-a prospective single-center cohort study.

Liver transplantation (LT) is the first-line therapy in patients with transthyretin (TTR) amyloidosis and progressive familial amyloid polyneuropathy (FAP). Explanted organs from these patients can be used for domino liver transplantation (DLT). After DLT, de novo amyloidosis may develop in domino recipients (DR). Data were collected prospectively in a transplant database. Electroneurography by nerve conduction velocity (NCV), quantitative sensory testing, heart rate variability (HRV), sympathetic skin response, orthostatic reaction (tilt table test), transthoracic echocardiography, cardiac MRI and organ biopsy results were evaluated. The cohort included 24 FAP- (11 Val30Met, 13 nonVal30Met) and 23 DR-patients. DR symptoms referred to post-DLT only, while those of FAP patients were both pre- and post-transplantation. Symptoms of TTR-amyloidosis in Val30Met and Non-Val30Met patients pre- and post-LT were similarly distributed. Biopsy-proven de novo amyloidosis occurred in 4/23 DR after a mean observation of 10 years. Analysis for manifestations of amyloidosis only included patients with available 5-year follow-up data (n = 13 FAP, n = 12 DR). Compared to Val30Met FAP patients pre-LT, Val30Met DR patients had better NCV (P = 0.04) and HRV (P = 0.015). In the Non-Val30Met group no differences were found between DR and FAP patients pre-LT. TTR-amyloidosis symptoms showed no differences in FAP patients pre- and 5 years post-LT, irrespective of Val30Met status. In DR patients, de novo amyloidosis occurred earlier than expected. Therefore, recipients for DLT need to be carefully selected and followed.

Targeted next-generation sequencing of cancer genes in poorly differentiated thyroid cancer.

Poorly differentiated thyroid carcinoma (PDTC) is a rare malignancy with higher mortality than well-differentiated thyroid carcinoma. The histological diagnosis can be difficult as well as the therapy. Improved diagnosis and new targeted therapies require knowledge of DNA sequence changes in cancer-relevant genes. The TruSeq Amplicon Cancer Panel was used to screen cancer genomes from 25 PDTC patients for somatic single-nucleotide variants in 48 genes known to represent mutational hotspots. A total of 4490 variants were found in 23 tissue samples of PDTC. Ninety-eight percent (4392) of these variants did not meet the inclusion criteria, while 98 potentially pathogenic or pathogenic variants remained after filtering. These variants were distributed over 33 genes and were all present in a heterozygous state. Five tissue samples harboured not a single variant. Predominantly, variants in P53 (43% of tissue samples) were identified, while less frequently, variants in APC, ERBB4, FLT3, KIT, SMAD4 and BRAF (each in 17% of tissue samples) as well as ATM, EGFR and FBXW7 (each in 13% of tissue samples) were observed. This study identified new potential genetic targets for further research in PDTC. Of particular interest are four observed ERBB4 (alias HER4) variants, which have not been connected to this type of thyroid carcinoma so far. In addition, APC and SMAD4 mutations have not been reported in this subtype of cancer either. In contrast to other reports, we did not find CTNNB1 variants.

Proteasome inhibitors prevent bi-directional HER2/estrogen-receptor cross-talk leading to cell death in endocrine and lapatinib-resistant HER2+/ER+ breast cancer cells.

Amplification and/or overexpression of the human epidermal growth factor 2 (HER2) oncogene occurs in about 13-15% of invasive breast cancer and triggers breast cancer cell proliferation, survival and metastatic progression. Around half of all breast cancers with HER2 overexpression co-express hormone receptors (HR) such as those for estrogen and progesterone. Aberrant signaling through HER2 and other members of the HER-family mediates endocrine-resistance in estrogen receptor alpha (ERα) positive breast cancer. On the other hand, ERα co-expression has been shown to attenuate the efficiency of anti-HER2 therapies. These findings indicate that HER2 and ERα synergize to escape from both anti-ERα and anti-HER2-targeted therapies. Rationally designed clinical trials that combine endocrine therapy with anti-HER2 agents to interfere with HER2/ERα cross-talk have been conducted. However, the outcome of these trials suggests that novel therapeutic approaches are needed to further improve inhibition of HER2 and other HER-family members in conjunction with a more efficient ERα blockade. Here, we demonstrate that carfilzomib and bortezomib stabilize the HER2-specific protein tyrosine phosphatase BDP1 leading to decreased HER2 autophosphorylation, reduced HER2 activity and subsequently attenuated activation of the PI3K/Akt-pathway, together with blockade of ERα expression. We further observed that proteasome inhibitors (PIs) reverse autophosphorylation and thereby inhibit the activity of constitutively active mutant HER2. We also demonstrate that PIs cause cell death in lapatinib and endocrine-resistant HER2+/ER+ breast cancer cells. These findings suggest that PIs might have the potential to improve the management of HER2+/ER+ breast cancer patients by efficiently disrupting the bi-directional HER2/ERα cross-talk.

Comprehensive Biomarker Analyses in Patients with Advanced or Metastatic Non-Small Cell Lung Cancer Prospectively Treated with the Polo-Like Kinase 1 Inhibitor BI2536.

BACKGROUND: Polo like kinase 1 (PLK1) is frequently upregulated in tumors and is thus viewed as a promising therapeutic target in various cancers. Several PLK1 inhibitors have recently been developed and clinically tested in solid cancers, albeit with limited success. So far, no predictive biomarkers for PLK1 inhibitors have been established. To this end, we conducted a post-hoc biomarker analysis of tumor samples from non-small cell lung cancer (NSCLC) patients treated with the PLK1 inhibitor BI2536 in a phase II study. METHODS: We analyzed formalin-fixed paraffin-embedded surplus tumor tissue from 47 study patients using immunohistochemistry (IHC) and DNA sequencing of KRAS, EGFR, BRAF, and PIK3CA. RESULTS: KRAS-mutated patients showed numerically prolonged progression-free survival, but statistical significance was not established. Interestingly, when pathways rather than single genes were analyzed, a positive correlation between IHC staining of activated ERK (p-ERK) and mutated KRAS was detected, whereas KRAS mutation status was found to be negatively correlated with activated AKT (p-AKT). CONCLUSION: With this hypothesis-generating study in BI2531-treated patients, we could not establish a correlation between KRAS mutations and relevant clinical endpoints. Future clinical trials with concomitant systematic biosampling and comprehensive molecular analyses are required to identify biomarkers predictive for response to PLK1 inhibitors.

Loss of organic cation transporter 3 (Oct3) leads to enhanced proliferation and hepatocarcinogenesis.

BACKGROUND: Organic cation transporters (OCT) are responsible for the uptake of a broad spectrum of endogenous and exogenous substrates. Downregulation of OCT is frequently observed in human hepatocellular carcinoma (HCC) and is associated with a poor outcome. The aim of our current study was to elucidate the impact of OCT3 on hepatocarcinogenesis. METHODS: Transcriptional and functional loss of OCT was investigated in primary murine hepatocytes, derived from Oct3-knockout (Oct3-/-; FVB.Slc22a3tm1Dpb ) and wildtype (WT) mice. Liver tumors were induced in Oct3-/- and WT mice with Diethylnitrosamine and Phenobarbital over 10 months and characterized macroscopically and microscopically. Key survival pathways were investigated by Western Blot analysis. RESULTS: Loss of Oct3-/- in primary hepatocytes resulted in significantly reduced OCT activity determined by [3H]MPP+ uptake in vivo. Furthermore, tumor size and quantity were markedly enhanced in Oct3-/- mice (p<0.0001). Oct3-/- tumors showed significant higher proliferation (p<0.0001). Ki-67 and Cyclin D expression were significantly increased in primary Oct3-/- hepatocytes after treatment with the OCT inhibitors quinine or verapamil (p<0.05). Functional inhibition of OCT by quinine resulted in an activation of c-Jun N-terminal kinase (Jnk), especially in Oct3-/- hepatocytes. CONCLUSION: Loss of Oct3 leads to enhanced proliferation and hepatocarcinogenesis in vivo.

Detection of cellular senescence within human invasive breast carcinomas distinguishes different breast tumor subtypes.

Oncogene-induced senescence is thought to act as a barrier to tumorigenesis by arresting cells at risk of malignant transformation. Nevertheless, numerous findings suggest that senescent cells may conversely promote tumor progression through the development of the senescence-associated secretome they produce. It is likely that the composition and the physiological consequences mediated by the senescence secretome are dependent on the oncogenes that trigger the senescence program. Breast cancer represents a heterogenous disease that can be divided into breast cancer subtypes due to different subsets of genetic and epigenetic abnormalities. As tumor initiation and progression of these breast cancer subtypes is triggered by diverse oncogenic stimuli, differences in the senescence secretomes within breast tumors might be responsible for tumor initiation, progression, metastasis and therapeutic response. Many studies have addressed the role of senescence as a barrier to tumor progression using murine xenograft models. However, few investigations have been performed to elucidate the degree to which senescent tumor cells are present within untreated human tumors, and if present, whether these senescent tumor cells may play a role in disease progression. In the present study we analysed the appearance of senescent cells within invasive breast cancers. Detection of cellular senescence by the use of SAß-galactosidase (SAß-gal) staining within invasive breast carcinoms from 129 untreated patients revealed differences in the amount of SAß-gal+ tumor cells between breast cancer subtypes. The highest percentages of SAß-gal+ tumor cells were found in HER2-positive and luminal A breast carcinomas whereas triple negative tumors showed either little or no positivity.